Endocrinocarcinomas (carcinoids and their variants) of the duodenum. An evaluation of 927 cases.

This study was undertaken to supplement our previous analysis of 635 duodenal carcinoids to give both wider and different viewpoints on a larger series of duodenal endocrinocarcinomas, and to provide up-to-date clinicopathologic information regarding these neoplasms. A total of 927 cases of such neoplasms of the duodenum were collected from the Niigata Registry for gut-pancreatic endocrinomas, consisting of the carcinoid group with 897 cases, 857 typical carcinoids and 40 atypical varieties, and the variant group with 30 remaining endocrinocarcinomas expressed by various terminology. Significant statistical differences between these two groups were evident in various aspects: in sites of tumor growth, aggressiveness of invasion to the extra-duodenal structures, rates and sites (liver, lymph nodes and bone) of metastases, average tumor-size, immunohistochemistry of gastrin and serotonin, rates of recurrence, five-year survival rates and others. In addition, a close similarity between these two groups was noted in several aspects of histology, histochemistry and immunohistochemistry, rendering the variant group in a member of the carcinoid family. Regarding the carcinoid group in comparison with that in other organs may be summarized as follows: a reasonable male/female ratio of 1.39, a reasonable average age of 55.9 years, a high typical/atypical ratio of 21.4, a relatively small average tumor-size of 17.7 mm, a relatively low metastasis rate of 27.4%, a high histologic B-type dominance of 75.5%, a high postoperative survival rate of 83.3% and a reasonable incidence of the carcinoid syndrome of 3.1%.